Rapid LPE crystal growth

A method of growing an epitaxial layer of a material on a surface of a substrate from a solution, comprising the steps of positioning said surface of the substrate at a first side of a first channel having at the location of said substrate a breadth which is substantially greater than the depth of said first channel, said first channel having an inlet communicating with a reservoir of solution and an outlet communicating with a receiver of solution, forcing at least part of said solution from the reservoir to enter the first channel via said inlet so as to flow through the first channel across said surface of said substrate and to leave the first channel via said outlet and to enter the receiver, said first channel being configured such that streamline flow of said at least part of said solution takes place in the region of said surface of said substrate, causing a coolant fluid to flow in a second channel while in heat exchange relationship with the substrate to lower the temperature of said substrate relative to the saturation temperature of said at least part of said solution entering said first channel, thereby to induce the growth of an epitaxial layer of material on said surface, said growth of said epitaxial layer of said material on said surface of said substrate taking place during said flow of said solution through said first channel.